Blade-type drill bit



June 29, 1965 L. w. SHORT 3,191,698

BLADE-TYPE DRILL BIT Filed May 17. 1962 ORNE YS United States Patent3,191,698 BLADE-TYPE DRILL BIT Lot William Short, Dallas, Tex., assignorto Drilling & Service, Inc., Dallas, Tex., a corporation of Texas FiledMay 17, 1962, Ser. No. 195,595 19 (Zlaims. (ill. 175-33) This inventionrelates to a blade-type drill .bit and more particularly to a drill bitusing hard, abrading elements, such as diamonds, arranged alonggenerally radially extending blade-like projecting ribs forming thecutting edges of the bit.

The present invention constitutes a modification of the bit describedand claimed in my United States Letters Patent No. 2,990,897, issuedJuly 4, 1961, and possesses certain advantages over the drill bit ofthat patent in the drilling of bore holes in earth formations,particularly with respect to a more economical use of diamonds, or otherhard abrasive abrading elements. In accordance with my presentinvention, I preferably employ the generally triangular configuration,when viewed in bottom plan view, that is shown in my aforesaid patent,but instead of providing abrading particles in closely spacedrelationship embedded in .the lower working face .and lateral reamingfaces substantially throughout their entire area, I embed, prefera bly,a single row of diamonds along the leading, or cut ting, edge of each ofa plurality of blade-like projecting ribs that extend radially outwardlyfrom near the center I of the lower face of the bit and upwardly alongthe lateral, segmental-cylindrical, reaming faces of the bit. Theprojecting blade-like ribs are formed between the lower surface of the.bit and the generally radially extending water grooves that also extendupwardly along the lateral reaming faces of the bit. The lower workingface of the bit on the other, or trailing, edge of each of the radiallyextending grooves is slightly offset axially upwardly and/ or inwardly,and is generally flattened to provide an abutment or bumper that is freeof abrading particles. The edge of the abutment at each groove will bereferred to as the trailing edge of the abutment.

Additionally, provision is made for conducting a drilling fluid underhigh pressure into each of the radially extending grooves intermediatethe length thereof, and the grooves are preferably restricted incross-section outwardly toward the periphery of the lower working faceto insure a high velocity flow of drilling fluid over and around theabrading elements to cool the same and upwardly along the extensions ofsaid grooves in the lateral faces of the bit to carry away cuttings andloose material formed during the drilling operation. For the purpose ofremoving larger cuttings, a groove of greater crosssectional area thanthe grooves previously mentioned extends from a closed recess near thecenter of the working face of the bit outwardly to and through anon-reaming facet that lies wholly within the lateral periphery of thebit generated by the segmental-cylindrical faces thereof.

It is therefore an important object of this invention to provide a drillbit of a blade-type construction that makes a more economical use of thediamonds, or other abrading elements, and that possesses noveloperational advantages in the drilling of bore holes in certain types ofearth formations.

It is a further object of this invention to provide a drill bit ofimproved construction in which there is a more eflicient utilization inoperation of high velocity streams of drilling fluid in the cooling ofthe abrading elements and in the removal of the cuttings and looseparticles of earth formation formed or encountered in drilling.

It is a further object of this invention to provide, in a drill hit, anarrangement of generally radially extending water grooves, each formingwith the lower working face of the bit a blade-like projecting rib thatconstitutes the leading edge and that is set with a row of abradingelements along its length, with the opposite or trailing edge of therespective grooves slightly offset axially upwardly and/or inwardly, andwith the lower face of the bit adjacent such trailing edge providing agenerally flattened abutment or bumper that cooperates by contact withthe bottom of the bore hole to cause a high velocity flow of thedrilling fluid over the leading edge of the corresponding blade to cooland free the abrading elements set therein for their cutting action.

It is a further important object of this invention to provide ablade-type of drill bit the lower working face of which is provided nearits center with a recess from which extend water grooves that are ofrestricted cross-sectional area toward the periphery of the Working faceand that are supplied with a drilling fluid intermediate their lengthsfor high velocity flow over the abrading elements that are set in theleading blade-type edges of such grooves.

Other objects, features and advantages of this invention will becomeapparent to one skilled in the art from the following description of theembodiments of the invention illustrated in the accompanying drawings,in which:

FIGURE 1 is a bottom plan view of a drill bit embodying the features ofmy invention;

FIGURE 2 is a sectional view taken substantially along the line II-II ofFIGURE 1;

FIGURE 3 is a sectional view taken substantially along the broken lineIII-III of FIGURE 2; and

FIGURE 4 is a reduced, fragmentary elevational View taken substantiallyalong the line IV-IV of FIGURE 1.

As shown on the drawings:

The drill bit illustrated in the drawings is one adapted to be attachedto the lower end of a rotary drill stem in the drilling of oil wells andthe like, wherein the drill stem (not shown) is rotated by a rotarytable (not shown) and wherein a drilling fluid, such as any of thosecommonly used for the purpose, is circulated down through the drill stemand discharged through the lower working end of the drill bit. Thedrilling fluid is for the purpose of cooling the abrading elements ofthe bit and of carrying away from the bottom of the bore hole theparticles of earth formation generated by the abrading action of thedrill bit or otherwise present in the bottom of the hole. As is wellunderstood, the drilling fluid is usually a water suspension of a:bentonite clay or the like, and is pumped down to the drill bit .underconsiderable pressure. As will later be explained, the particulararrangement of fluid discharge bores and water grooves in the bit of myinvention, in combination with the configuration of the lower Workingface of the bit and the constriction of the water grooves toward theperiphery of such Working face results in a higher velocity flow ofdrilling fluid over and around the abrading elements during theircutting action than has heretofore been usually the case.

With more specific reference to the drawings, the reference numeral 10indicates generally a drill bit of my invention, provided at its upperend with a shank 11 having an axially extending recess 12 that is openat the top for receiving the drilling fluid from the drill stern andthat is counterbored at the bottom, as at 13. The shank 11 is thushollow, and is provided with an externally tapered, threaded portion 14for attachment to the drill stem. The body of the bit, indicated at 15,is carried by the shank 11 at the lower end thereof and is usuallyintegral therewith. Said body 15 is preferably of a generallytriangularly shaped configuration when viewed in bottom plan, as inFIGURE 1.

As there shown, the body portion 15 comprises threesegmental-cylindrical lateral faces 16, 16a and 16b, between whichextend non-reaming facets 17, 17a and 17b, each of which is of greaterperipheral extent than any of the segmental-cylindrical reaming faces1%, 16:: Or 16b,

enemas and each of which lies wholly within the cylinder generated bysaid segmental-cylindrical lateral faces. While the non-reaming facets17, 17a and 17b are illustrated as being substantially fiat in FIG. 1,they may be arcuate, either convexly or concavely, so long as they liewholly Within the generated cylinder. As shown in FIG. 4, thenon-reaming facets, such as 1711-, extend laterally upwardly to near thetop of the enlarged body portion of the bit, while the reaming lateralfaces, such as 16 and 16b, terminate in a transverse plane, indicated atP, above which the body of the bit is smoothly tapered, as at 19, tomerge with the lower cylindrical end of the shank 11.

The lower working face 20 is provided near its center with a generallyconical blind recess, indicated at R (FIG. 2) from which the surfaceextends outwardly through a convexly smooth peripheral surface portion21 to the segmental-cylindrical surfaces 16, 16a and 16b. Three watergrooves 22, 22a and 22b extend from near the upper closed apex of saidrecess R in a generally radially outwardly direction and then along theconvex portions 21 and upwardly along the respectivesegmentalcylindrical lateral faces 16, 16a and 16b, preferably throughthe tapered surface 19 (FIG. 2).- Said water grooves 22, 22a and 22b areconstricted in their crossa sectional area toward the peripheral extentthereof, as at 23, 23a and 23b for a purpose that will laterv appear.Bores 24, 24a and 24b extend downwardly in an inclined direction fromthe counterbore 13 of the shank recess 12 into the respective grooves22, 22a and 22b, near the midpoints of the length thereof. Thus, thedrilling fluid introduced into the recess 12 of the hollow shank 11 isdischarged, during operation, through the respective bores 24, 24a and24b into the corresponding water grooves 22, 22a and 22b. Thecross-sectional area of each of said bores 24, 24a and 24b, isconsiderably greater than the cross-sectional area of the correspondingwater grooves so as to increase the pressure and therefore the velocityof the drilling fluid as the same enters and flows through the watergrooves. The restriction of said water grooves toward their respectiveperipheral extents tends to build up a back pressure causing thedrilling fluid to flow inwardly through the respective grooves towardthe apical recess portion R for discharge laterally therefrom through anenlarged water course 25, which constitutes an extension of the watergroove 22a and that opens for discharge of the drilling fluid throughthe non-reaming facet 17b. Larger portions of earth formation, andparticularly those broken off within the apical recess R, can thus bedischarged through said enlarged water course 25 and pass freelyupwardly between the non-reaming facet 17b and the wall of the borehole.

As viewed in FIGURE 1, with the bit turning counterclockwise, asindicated by the arrow, that edge of each of the grooves 22, 22a and 22bwhich constitutes the diamond set blade will be termed the leading edge,and the other will be termed the trailing edge. With this understanding,the respective grooves 22, 22a and 22b have trailing edges 26, 26a and26b, and have leading edges 27, 27a and 27b. The respective leadingedges, as best illustrated in FIGURE 3 by the leading edge 27a, areconstituted by blade-like projecting ribs formed at the junction of theadjacent portion of the lower working face 20 and the wall of thegroove, in this case, the groove 2211. Since all of the projecting ribsare similar, only that best shown in FIGURE 3 need be described. Theportion of the lower working face indicated by the reference numeral 20aslopes upwardly and away from the projecting rib 27a, while the adjacentwall 28a of the groove 22a lies in a substantially vertical plane, withthe result that a bladelike rib is formed at the junction of the twosurfaces 20a and 28a. A single row of closely set diamonds 29 isembedded in the edge 27a formed by such blade-like projecting rib, andas shown in FIGURES 1 and2, this single row of diamonds extends fromwithin the blind recess R continuously along the radial length of theedge 27a and upwardly along substantially the full extent thereof on thelateral segmental cylindrical reaming face 16a. The diamonds, or otherhard abrading elements, are set relatively closely together, preferablybut not necessarily in a single row right in the very edge itself, andare suitably embedded in the matrix or alloy of which the working faceof the bit is constituted so as to exert maximum cutting, or abrading,action throughout the usefullife of the diamonds during the drillingoperation.

The other, or trailing edges of the grooves 22, 22a and 22b, are allgenerally similar and all generally follow the contour of thecorresponding leading edge of the respective grooves but in a planeslightly offset upwardly and/ or inwardly from a transverse planepassing through the diamond-set edges 27, 27a and 27b. This can best beunderstood by reference to FIGURE 3, wherein the letter D represents theamount of offset between the plane of the trailing edge 26a and that ofthe leading edge 27a. The distance D may vary from as little as from bior so, up to A" or greater, depending upon the nature of the earthformation to be drilled, the fluid energy available at the bit, thetorque limits of the drill stem and the weight available to be appliedto the bit during drilling. The trailing edge 26a is preferably smoothlyrounded at the junction of the adjacent groove wall 36a and portion 31aof the working face of the bit. Said working face portion 31a ispreferably nearly flat, or only slightly sloping, for a substantialdistance away from the edge 26a, thereby forming, in effect, anabutment, or bumper, that minimizes the flow of drilling fluid betweensuch abutment and the bottom of the bore hole. Said abutment 31a and thesimilar abutments 31 and 31b, are all free from abrading particles, ordiamonds, and therefore, exert no cutting or abrading action. They do,however, limit the bite taken by the bladetype edges by the fact thatthe abutment, or bumper surface, rests against the bottom of the hole atall times during drilling.

In operation, as a result of the correlation between the flow capacityof the bores 24, 24a and 24b, and the corresponding water grooves 22,22a and 22b, and also as a result of the restriction of said watergrooves toward their peripheral extent, the drilling fluid flows alongsaid water grooves at a relatively high velocity to carry looseparticles of earth formation away from the bottom of the hole. Inparticular, by virtue of the blade-like projecting ribs 27, 27a and 27b,and their corresponding, upwardly offset abutmen'ts 3:1, 31a and 31bextending away from the leading edges 26, 26a and 26b, there is a highvelocity flow of' the drilling fluid over and around the diamonds 29 inthe leading edges of the water grooves and this serves to cool thediamonds and to free them from particles formed by the abrading orcutting action of the diamonds. Inasmuch as the water groove 22:: issomewhat longer than the water grooves 22 and 22b, the bore 24asupplying said water groove 22a is of larger capacity than either of thebores 24 or 24b. Also, the blade-type projecting rib, or edge 27a, islonger than the other edges 27 and 27b, in that the blind recess R isofiset from the true axis of the drill bit in the direction toward thenon-reaming lateral facet 17b and the edge 27a continues for the lengthof said water groove 22a up into said recess R. Consequently, there issome ab rading action caused by the diamonds 29 that lie within theapical recess R, and the particles of earth formation resulting fromsuch abrading action of those diamonds are carried along with the streamof drilling fluid that discharges radially outwardly through theenlarged water groove 25 through the nonreaming facet 17b. Because ofthe axially offset position of the conical recess R, there is more of acrushing than of an abrading action, with a result that larger particlesof earth formation are produced within the extent of the recess, andthese larger particles are readily accommodated by the largercross-sectional area of the water groove 25 and by reason of therelatively large free space between the lateral facet 17band the wall ofthe bore hole.

In general, the diamonds 29 are selected of a size and shape suited forthe purpose, and are set along the leading edges 27, 27a and 27b in sucha manner as to accentuate the blade-type projecting ribs afforded by thecontour of the lower working face 20 and the water grooves 22, 22a and2212. As stated, the rows of said diamonds 29 are preferably only onediamond in width. This results in a great saving in the cost ofdiamonds, as compared with prior art drill bits in which the diamondsare set in closely spaced relation over substantially the entire lowerand lateral working faces of the drill bit.

It will, of course, be understood that various details of constructionand arrangement may be varied somewhat without departing from theprinciples of this invention, and it is, therefore not the purpose tolimit the patent granted hereon otherwise than necessitated by the scopeof the appended claims.

I claim as my invention:

1. A drill bit comprising:

a bit body having at its upper end an axial recess and at its lower enda working face,

said working face beingrforrned with a blind recess near the centerthereof and with a plurality of water grooves extending from said recessto the periphery of said working face,

the working face along a corresponding one side of each of said groovesforming with the adjacent groove wall a narrow radially extendingblade-like projecting rib,

each of said ribs being set with closely spaced abrasive particles alongthe length thereof and presenting abrasive cutting edges toward thegroove side thereof,

the working face along the other side of each groove being generallyflat and ofiset axially upwardly of a plane transverse to the axis andpassing through said abrasive cutting edges to form a bumper areaextending continuously from said groove side to the next succeeding rib,

there being a bore through said bit body from said axial recess openinginto each of said grooves radially outwardly of said blind recess todischarge drilling fluid into each of said grooves for high elocity fiowacross said recess and over said abrasive cutting edges the full lengthsthereof,

said bumper areas serving to limit the bite taken by said blade-likeprojecting ribs.

2. A drill bit comprising:

a bit body having at its upper end an axial recess, at its lower end aworking face and at its periphery lateral segmental cylindrical reamingfaces with intervening radially inward non-reaming facets,

said working face being formed with a blind conical recess near thecenter thereof and with a plurality of water grooves extending from andacross said recess to the periphery of said working face and upwardlyalong said segmental cylindrical reaming faces,

the working face along a corresponding one side of each groove formingwith the adjacent groove Wall a narrow radially extending blade-likeprojecting rib,

each of said ribs being set with substantially a single row of diamondsextending therealong and presenting and abrasive cutting edge toward thegrooved side thereof,

the working face along the other side of each groove being generallyfiat and offset axially upwardly of a plane transverse to the axis andpassing through said abrasive cutting edges to form a bumper arealimiting the bite of said ribs,

there being a bore .through said bit body from said axial recess openinginto each of said grooves radially outwardly of said recess to dischargedrilling fluid into each of'said grooves for high velocity flow throughsaid grooves, across said recess and over said abrasive cutting edges.

3. A drill bit comprising:

a hollow cylindrical shank,

an enlarged bit body at the lower end of said shank having a lower faceof generally triangular configa uration in bottom plan merging at itsperiphery into three coaxial segmental cylindrical lateral reaming facesand three intermediate non-reaming facets each of greater peripheralextent than any of said segmental cylindrical faces and lying radiallywholly within the latter,

said lower face having near the center thereof a closed recess and threewater grooves extending outwardly therefrom along said lower face andupwardly along said segmental cylindrical lateral faces,

said lower face along a cor-responding one side of each of said groovesforming with the adjacent groove wall a narrow radially extendingblade-like projecting rib and along each corresponding other side ofsaid grooves forming an abutment offset axially upwardly of thecorresponding rib and conforming generally in contour to one of saidribs throughout the length thereof,

each of said ribs along the adjacent groove wall edge bein set withabrasive particles extending from adjacent said recess outwardly alongsaid groove wall edge,

there being a bore through said bit body from said hollow shank openinginto each of said grooves radially outwardly of said recess to dischargedrilling fluids into said grooves for high velocity flow therealong andacross said recess and for cooling said abrasive particles in said ribsalong said grooves and the upward extensions thereof.

4. A drill bit as defined in claim 3, wherein, said grooves arerestricted in cross-section toward the periphcry of said lower face.

5. A drill bit as defined in claim 3, wherein, an additional watergroove extends from said recess in substantially diametrical alignmentwith one of said three grooves to the nearest of said non-reaming facetsfor discharge of drilling fluid upwardly along said facet.

6. A drill bit comprising:

a bit body having at its upper end an axial recess and at its lower enda working face smoothly merging at its periphery into upwardly extendinglateral reaming faces and intermediate radially inwardly relievednon-reaming facets,

said working face being formed near the center thereof with a closedrecess and with a plurality of water grooves extending from and acrosssaid recess to the periphery of said working face and upwardly alongsaid lateral reaming faces of said bit,

a radially extending blade-like projecting rib formed along acorresponding edge of each of said grooves, substantially the fulllength thereof,

the working face along the other side of each of said grooves extendingback from one groove edge to the next groove edge to form therebetween agenerally fiat abutment similar in contour to the contour :of saidprojecing rib but offset axially upwardly from said rib substantiallythe full length thereof to limit the bite vof said rib during drilling,

there being a bore through said bit body from said axial recess to eachof said grooves radially outwardly of said recess to discharge drillingfluid into said grooves for high velocity flow therealong and acrosssaid recess,

and a narrow row of abrasive particles set along each :of saidblade-like projecting ribs for substantially the full length thereof,

the working face being otherwise free of abrasive particles.

, 7, A drill bit as defined in claim 6, wherein, there is an addtionalgroove, but without any bore leading directly thereinto, formedsubstantially as a diametri-cal continuation of one of said first-namedgrooves on the other side of said closed recess from said one groove anddischarging along a radially inwardly relieved non-reaming facet.

'8. A drill bit as defined in claim 6, wherein, the lower 'working faceis of generally triangular configuration in plan and is defined by threesegmental cylindrical lateral reaming faces including upwardcontinuations of said ribs and three intermediate non-reaming facetseach of the latter of which is of greater peripheral extent than each ofsaid segmental cylindrical faces and lies wholly Within the cylindergenerated by said segmental cylindrical faces.

"9. A drill bit comprising:

a bit body having at its upper end an axial recess and at its lower enda working face,

said working face being formed with a plurality of water groovesextending from near the center of said face to the periphery thereof,

each of said water grooves being restricted in crosssection toward theperiphery of said working face, the working face along the correspondingone side of each groove forming with the adjacent groove wall ablade-like projecting rib,

each of said ribs being set with closely spaced abrasive particles alongthe length thereof and presenting abrasive cutting edges toward .thegroove side thereof,

the working face along the other side of each groove being generallyflat and offset axially upwardly of the plane transverse to the axis andpassing through said abrasive cutting edges,

there being a bore through said bit body from said axial recess to eachof said grooves to discharge drilling fluid into each of said groovesfor high velocity flow with said abrasive cutting edges,

each of said bores being of larger cross-sectional area than that of agroove into which said bore discharges, 7

10. A drill bit comprising:

a bit body having at its upper end an axial recess and at its lower enda working face,

said working face being formed with a plurality of Water groovesextending from near the center of said face to the periphery thereof,

the working face along the corresponding one side of each groove formingwith the adjacent groove wall a blade-like projecting rib,

each of said ribs being set with a single row of closely spaced diamondsextending therealong and presenting abrasive cutting edges to the grooveside thereof,

the Working face along the other side of each groove being generallyflat and offset axially upwardly of a plane transverse to the axis andpassing through said abrasive cutting edges,

there being a bore through said bit body from said axial recess to eachof said grooves to discharge drilling fluid into each of said groovesfor high velocity flow over said abrasive cutting edges.

References, Cited by the Examiner UNITED STATES PATENTS 2,371,489 3/45\Villiams 175329 2,371,490 3/45 Williams 175-3-29 2,931,630 4/60 Grady175-330 2,990,897 7/61 Short 175330 2,998,088 8/61 Pennington 175-329FOREIGN PATENTS 1,249,346 11/ France.

CHARLES E. OCONNELL, Primary Examiner.

10. A DRILL BIT COMPRISING: A BIT BODY HAVING AT ITS UPPER END AN AXIALRECESS AND AT ITS LOWER END A WORKING FACE, SAID WORKING FACE BEINGFORMED WITH A PLURALITY OF WATER GROOVES EXTENDING FROM NEAR THE CENTEROF SAID FACE TO THE PERIPHERY THEREOF, THE WORKING FACE ALONG THECORRESPONDING ONE SIDE OF EACH GROOVE FORMING WITH THE ADJACENT GROOVEWALL A BLADE-LIKE PROJECTING RIB, EACH OF SAID RIBS BEING SET WITH ASINGLE ROW OF CLOSELY SPACED DIAMONDS EXTENDING THEREALONG ANDPRESENTING ABRASIVE CUTTING EDGES TO THE GROOVE SIDE THEREOF, THEWORKING FACE ALONG THE OTHER SIDE OF EACH GROOVE BEING GENERALLY FLATAND OFFSET AXIALLY UPWARDLY OF